Effects of growth temperature on maximal specific growth rate, yield, maintenance, and death rate in glucose-limited continuous culture of the thermophilic Bacillus caldotenax

Bioenergetics of sulfur reduction in the hyperthermophilic archaeon Pyrococcus furiosus

“…Therefore, the effect of So is not due to a lowering of the H2 concentration. In fact, an appreciable decrease in biomass yield was noted only when the H2 (19,20,29,55,56). However, the calculated maximal yield coefficients for P. furiosus are quite comparable to those reported for representative mesophiles and thermophiles growing on glucose (see Table 3), reinforcing the assertion that growth at extremely high temperatures is not necessarily inefficient (7,31).…”

“…It is possible that the cultures were limited by nitrogen in the form of a peptide or amino acid present in the extracts and that raising the concentration of the extracts would lead to a decrease in m. Another possibility is that the particular growth conditions chosen in this study are suboptimal in some way and that these values represent a stressed state of growth such as above the optimal temperature or below the optimal pH for efficient growth (21,23,35,37,50). It has also been reported that some thermophiles have both high maximal yield coefficients and high maintenance coefficients, resulting in overall growth efficiencies comparable to those of mesophiles (7,29). However, the negative value determined for msi is physically meaningless and can be attributed to some degree of scatter in the data used for the calculation.…”

Biooxidation capacity of the extremely thermoacidophilic archaeonMetallosphaera sedula under bioenergetic challenge

“…By compromising cellular bioenergetics in various ways, iron or sulfur oxidation may be enhanced as a means to compensate for a nonideal situation. In fact, energy coupling by thermoacidophiles at high temperature and low pH may be relatively inefficient even under normal growth conditions in view of the high maintenance coefficients and the high membrane permeability to protons found for these organisms when compared to mesoacidophiles (De Vrij et al, 1988;Farrand et al, 1983;Konings et al, 1992;Kuhn et al, 1980;McKay et al, 1982). On the other hand, Elferink et al (1994) showed Sulfolobus acidocaldarius has a relatively Within the normal growth temperature range for M. sedula, specific iron oxidation rates increase with temperature; at 73 and 79°C, cell densities were comparable although iron pyrite oxidation rates were 1.6-fold higher at the higher temperature.…”

Bioenergetic studies of coal sulfur oxidation by extremely thermophilic bacteria. Final report, September 15, 1992--August 31, 1997

“…By compromising cellular bioenergetics in various ways, iron or sulfur oxidation may be enhanced as a means to compensate for a nonideal situation. In fact, energy coupling by thermoacidophiles at high temperature and low pH may be relatively inefficient even under normal growth conditions in view of the high maintenance coefficients and the high membrane permeability to protons found for these organisms when compared to mesoacidophiles (De Vrij et al, 1988;Farrand et al, 1983;Konings et al, 1992;Kuhn et al, 1980;McKay et al, 1982). On the other hand, Elferink et al (1994) showed SulfoZobus acidocaldarius has a relatively low proton permeability at 80°C compared to Escherichia coli or Bacillus stearothennophiZus.In any case, Extreme thermoacidophiles presumably need to invest additional metabolic energy for maintenance of a suitable intracellular pH under stress.…”